<!DOCTYPE html>
<html lang="en">

<head>
  <title>类选择器演示</title>
  <style>
    .c1 {
      color: green;
      text-align: center;
      font-size: 30px;
    }

    .c2 {
      color: red;
      text-align: center;
      font-size: 30px;
    }
  </style>


</head>

<body>

  <div class="c1">道可道，</div>
  <div class="c1">非常道。</div>
  <div class="c2">名可名，</div>
  <div class="c2">非常名。</div>

</body>

</html>